Dynamic balancing

[Gixxer Kevin]

I am getting a new set of tires (obviously) for my bike and the guy mounting them is telling me about a new type of balancing where they put little beads inside the tire. The theory is that the beads seek out the low spots inside the tire and balance it. I'm skeptical. Anybody have any experience with this?

[Bob]

No experience here, but have read many discussions re. this. When subjected to the test of physics and common sense, it pretty much looks like smoke and mirrors. Your skepticism is warranted. Not to mention they are a bigger hassle than slapping a couple weights on the wheel. The beads are tiny and it takes a while to get them into the tire thru the valve stem. The next time the tire is changed, where do all your beads go? So you buy more. How do the beads know exactly where to go to balance the wheel? Why does the mfgr. state that testing their theory using a commercial spin balancer won't show the "magical action" for some strange reason....? And so-on. It pretty much requires a leap of faith to use them. Big leap, lol. The users swear by them. But how would they even know they're working? New tires mounted without weights will often feel smooth as the vibes are absorbed by the suspension.

OK, flame suit on.

[Ed]

Agreed- no direct experience, but have doubts... although our front-load washing machine balances itself using the same basic concept

I've balanced my bike wheels separately with weights epoxied into the drop-center portion of the rim... since then, have been finding decent-brand tires (the Pirellis, Dunlops, and Michelins I've run, anyway) to be uniform enough to need very little weight to balance- if any- with my non-precise tools (the wheel bearings).

[Bob]

Here's something else that just occurred to me. The other day when I changed my rear tire, the inside was coated with a very sticky film of tire-mounting lube. How in the world can those tiny beads even move AT ALL in that muck?

[Brick]

Noooooo just don't do it!!! Just my $.02. YMMV.